1 /*****************************************************************************
2 * mpegvideo.c: parse and packetize an MPEG1/2 video stream
3 *****************************************************************************
4 * Copyright (C) 2001-2006 the VideoLAN team
7 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
8 * Eric Petit <titer@videolan.org>
9 * Gildas Bazin <gbazin@videolan.org>
10 * Jean-Paul Saman <jpsaman #_at_# m2x dot nl>
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
25 *****************************************************************************/
27 /*****************************************************************************
28 * Problem with this implementation:
30 * Although we should time-stamp each picture with a PTS, this isn't possible
31 * with the current implementation.
32 * The problem comes from the fact that for non-low-delay streams we can't
33 * calculate the PTS of pictures used as backward reference. Even the temporal
34 * reference number doesn't help here because all the pictures don't
35 * necessarily have the same duration (eg. 3:2 pulldown).
37 * However this doesn't really matter as far as the MPEG muxers are concerned
38 * because they allow having empty PTS fields. --gibalou
39 *****************************************************************************/
41 /*****************************************************************************
43 *****************************************************************************/
46 #include <vlc_block.h>
47 #include <vlc_codec.h>
48 #include <vlc_block_helper.h>
49 #include "../codec/cc.h"
51 #define SYNC_INTRAFRAME_TEXT N_("Sync on Intra Frame")
52 #define SYNC_INTRAFRAME_LONGTEXT N_("Normally the packetizer would " \
53 "sync on the next full frame. This flags instructs the packetizer " \
54 "to sync on the first Intra Frame found.")
56 /*****************************************************************************
58 *****************************************************************************/
59 static int Open ( vlc_object_t * );
60 static void Close( vlc_object_t * );
63 set_category( CAT_SOUT );
64 set_subcategory( SUBCAT_SOUT_PACKETIZER );
65 set_description( _("MPEG-I/II video packetizer") );
66 set_capability( "packetizer", 50 );
67 set_callbacks( Open, Close );
69 add_bool( "packetizer-mpegvideo-sync-iframe", 0, NULL, SYNC_INTRAFRAME_TEXT,
70 SYNC_INTRAFRAME_LONGTEXT, VLC_TRUE );
74 /*****************************************************************************
76 *****************************************************************************/
77 static block_t *Packetize( decoder_t *, block_t ** );
78 static block_t *ParseMPEGBlock( decoder_t *, block_t * );
79 static block_t *GetCc( decoder_t *p_dec, vlc_bool_t pb_present[4] );
86 block_bytestream_t bytestream;
89 uint8_t p_startcode[3];
91 /* Sequence header and extension */
95 /* Current frame being built */
99 vlc_bool_t b_frame_slice;
103 /* Sequence properties */
105 int i_frame_rate_base;
106 vlc_bool_t b_seq_progressive;
107 vlc_bool_t b_low_delay;
108 int i_aspect_ratio_info;
111 /* Picture properties */
114 int i_picture_structure;
115 int i_top_field_first;
116 int i_repeat_first_field;
117 int i_progressive_frame;
119 mtime_t i_interpolated_dts;
120 mtime_t i_last_ref_pts;
121 vlc_bool_t b_second_field;
123 /* Number of pictures since last sequence header */
127 vlc_bool_t b_sync_on_intra_frame;
128 vlc_bool_t b_discontinuity;
131 vlc_bool_t b_cc_reset;
143 /*****************************************************************************
145 *****************************************************************************/
146 static int Open( vlc_object_t *p_this )
148 decoder_t *p_dec = (decoder_t*)p_this;
149 decoder_sys_t *p_sys;
151 if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', 'g', '1' ) &&
152 p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', 'g', '2' ) &&
153 p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', 'g', 'v' ) )
158 es_format_Init( &p_dec->fmt_out, VIDEO_ES, VLC_FOURCC('m','p','g','v') );
159 p_dec->pf_packetize = Packetize;
160 p_dec->pf_get_cc = GetCc;
162 p_dec->p_sys = p_sys = malloc( sizeof( decoder_sys_t ) );
165 p_sys->i_state = STATE_NOSYNC;
166 p_sys->bytestream = block_BytestreamInit( p_dec );
167 p_sys->p_startcode[0] = 0;
168 p_sys->p_startcode[1] = 0;
169 p_sys->p_startcode[2] = 1;
174 p_sys->p_frame = NULL;
175 p_sys->pp_last = &p_sys->p_frame;
176 p_sys->b_frame_slice = VLC_FALSE;
178 p_sys->i_dts = p_sys->i_pts = 0;
180 p_sys->i_frame_rate = 1;
181 p_sys->i_frame_rate_base = 1;
182 p_sys->b_seq_progressive = VLC_TRUE;
183 p_sys->b_low_delay = VLC_TRUE;
184 p_sys->i_seq_old = 0;
186 p_sys->i_temporal_ref = 0;
187 p_sys->i_picture_type = 0;
188 p_sys->i_picture_structure = 0x03; /* frame */
189 p_sys->i_top_field_first = 0;
190 p_sys->i_repeat_first_field = 0;
191 p_sys->i_progressive_frame = 0;
194 p_sys->i_interpolated_dts = 0;
195 p_sys->i_last_ref_pts = 0;
196 p_sys->b_second_field = 0;
198 p_sys->b_discontinuity = VLC_FALSE;
199 p_sys->b_sync_on_intra_frame = var_CreateGetBool( p_dec, "packetizer-mpegvideo-sync-iframe" );
200 if( p_sys->b_sync_on_intra_frame )
201 msg_Dbg( p_dec, "syncing on intra frame now" );
203 p_sys->b_cc_reset = VLC_FALSE;
206 p_sys->i_cc_flags = 0;
207 cc_Init( &p_sys->cc );
212 /*****************************************************************************
214 *****************************************************************************/
215 static void Close( vlc_object_t *p_this )
217 decoder_t *p_dec = (decoder_t*)p_this;
218 decoder_sys_t *p_sys = p_dec->p_sys;
220 block_BytestreamRelease( &p_sys->bytestream );
224 block_Release( p_sys->p_seq );
228 block_Release( p_sys->p_ext );
232 block_ChainRelease( p_sys->p_frame );
235 var_Destroy( p_dec, "packetizer-mpegvideo-sync-iframe" );
240 /*****************************************************************************
242 *****************************************************************************/
243 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
245 decoder_sys_t *p_sys = p_dec->p_sys;
248 if( pp_block == NULL || *pp_block == NULL )
253 if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
255 if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
257 p_sys->i_state = STATE_NOSYNC;
258 block_BytestreamFlush( &p_sys->bytestream );
260 p_sys->b_discontinuity = VLC_TRUE;
262 block_ChainRelease( p_sys->p_frame );
263 p_sys->p_frame = NULL;
264 p_sys->pp_last = &p_sys->p_frame;
265 p_sys->b_frame_slice = VLC_FALSE;
267 // p_sys->i_interpolated_dts =
268 // p_sys->i_last_ref_pts = 0;
270 block_Release( *pp_block );
275 block_BytestreamPush( &p_sys->bytestream, *pp_block );
279 switch( p_sys->i_state )
283 if( block_FindStartcodeFromOffset( &p_sys->bytestream,
284 &p_sys->i_offset, p_sys->p_startcode, 3 ) == VLC_SUCCESS )
286 p_sys->i_state = STATE_NEXT_SYNC;
289 if( p_sys->i_offset )
291 block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
293 block_BytestreamFlush( &p_sys->bytestream );
296 if( p_sys->i_state != STATE_NEXT_SYNC )
302 p_sys->i_offset = 1; /* To find next startcode */
304 case STATE_NEXT_SYNC:
305 /* TODO: If p_block == NULL, flush the buffer without checking the
308 /* Find the next startcode */
309 if( block_FindStartcodeFromOffset( &p_sys->bytestream,
310 &p_sys->i_offset, p_sys->p_startcode, 3 ) != VLC_SUCCESS )
316 /* Get the new fragment and set the pts/dts */
317 p_pic = block_New( p_dec, p_sys->i_offset );
318 block_BytestreamFlush( &p_sys->bytestream );
319 p_pic->i_pts = p_sys->bytestream.p_block->i_pts;
320 p_pic->i_dts = p_sys->bytestream.p_block->i_dts;
322 block_GetBytes( &p_sys->bytestream, p_pic->p_buffer,
325 /* don't reuse the same timestamps several times */
326 if( p_pic->i_buffer >= 4 && p_pic->p_buffer[3] == 0x00 )
328 /* We have a picture start code */
329 p_sys->bytestream.p_block->i_pts = 0;
330 p_sys->bytestream.p_block->i_dts = 0;
335 /* Get picture if any */
336 if( !( p_pic = ParseMPEGBlock( p_dec, p_pic ) ) )
338 p_sys->i_state = STATE_NOSYNC;
342 /* If a discontinuity has been encountered, then wait till
343 * the next Intra frame before continuing with packetizing */
344 if( p_sys->b_discontinuity &&
345 p_sys->b_sync_on_intra_frame )
347 if( p_pic->i_flags & BLOCK_FLAG_TYPE_I )
349 msg_Dbg( p_dec, "synced on intra frame" );
350 p_sys->b_discontinuity = VLC_FALSE;
351 p_pic->i_flags |= BLOCK_FLAG_DISCONTINUITY;
355 msg_Dbg( p_dec, "waiting on intra frame" );
356 p_sys->i_state = STATE_NOSYNC;
357 block_Release( p_pic );
362 /* We've just started the stream, wait for the first PTS.
363 * We discard here so we can still get the sequence header. */
364 if( p_sys->i_dts <= 0 && p_sys->i_pts <= 0 &&
365 p_sys->i_interpolated_dts <= 0 )
367 msg_Dbg( p_dec, "need a starting pts/dts" );
368 p_sys->i_state = STATE_NOSYNC;
369 block_Release( p_pic );
373 /* When starting the stream we can have the first frame with
374 * a null DTS (i_interpolated_pts is initialized to 0) */
375 if( !p_pic->i_dts ) p_pic->i_dts = p_pic->i_pts;
377 /* So p_block doesn't get re-added several times */
378 *pp_block = block_BytestreamPop( &p_sys->bytestream );
380 p_sys->i_state = STATE_NOSYNC;
387 /*****************************************************************************
389 *****************************************************************************/
390 static block_t *GetCc( decoder_t *p_dec, vlc_bool_t pb_present[4] )
392 decoder_sys_t *p_sys = p_dec->p_sys;
396 for( i = 0; i < 4; i++ )
397 pb_present[i] = p_sys->cc.pb_present[i];
399 if( p_sys->cc.i_data <= 0 )
402 p_cc = block_New( p_dec, p_sys->cc.i_data);
405 memcpy( p_cc->p_buffer, p_sys->cc.p_data, p_sys->cc.i_data );
407 p_cc->i_pts = p_sys->cc.b_reorder ? p_sys->i_cc_pts : p_sys->i_cc_dts;
408 p_cc->i_flags = ( p_sys->cc.b_reorder ? p_sys->i_cc_flags : BLOCK_FLAG_TYPE_P ) & ( BLOCK_FLAG_TYPE_I|BLOCK_FLAG_TYPE_P|BLOCK_FLAG_TYPE_B);
410 cc_Flush( &p_sys->cc );
414 /*****************************************************************************
415 * ParseMPEGBlock: Re-assemble fragments into a block containing a picture
416 *****************************************************************************/
417 static block_t *ParseMPEGBlock( decoder_t *p_dec, block_t *p_frag )
419 decoder_sys_t *p_sys = p_dec->p_sys;
420 block_t *p_pic = NULL;
423 * Check if previous picture is finished
425 if( ( p_sys->b_frame_slice &&
426 (p_frag->p_buffer[3] == 0x00 || p_frag->p_buffer[3] > 0xaf) ) &&
427 p_sys->p_seq == NULL )
429 /* We have a picture but without a sequence header we can't
431 msg_Dbg( p_dec, "waiting for sequence start" );
432 if( p_sys->p_frame ) block_ChainRelease( p_sys->p_frame );
433 p_sys->p_frame = NULL;
434 p_sys->pp_last = &p_sys->p_frame;
435 p_sys->b_frame_slice = VLC_FALSE;
438 else if( p_sys->b_frame_slice &&
439 (p_frag->p_buffer[3] == 0x00 || p_frag->p_buffer[3] > 0xaf) )
443 p_pic = block_ChainGather( p_sys->p_frame );
445 i_duration = (mtime_t)( 1000000 * p_sys->i_frame_rate_base /
446 p_sys->i_frame_rate );
448 if( !p_sys->b_seq_progressive && p_sys->i_picture_structure != 0x03 )
453 if( p_sys->b_seq_progressive )
455 if( p_sys->i_top_field_first == 0 &&
456 p_sys->i_repeat_first_field == 1 )
460 else if( p_sys->i_top_field_first == 1 &&
461 p_sys->i_repeat_first_field == 1 )
468 if( p_sys->i_picture_structure == 0x03 )
470 if( p_sys->i_progressive_frame && p_sys->i_repeat_first_field )
472 i_duration += i_duration / 2;
477 if( p_sys->b_low_delay || p_sys->i_picture_type == 0x03 )
479 /* Trivial case (DTS == PTS) */
480 /* Correct interpolated dts when we receive a new pts/dts */
481 if( p_sys->i_pts > 0 ) p_sys->i_interpolated_dts = p_sys->i_pts;
482 if( p_sys->i_dts > 0 ) p_sys->i_interpolated_dts = p_sys->i_dts;
486 /* Correct interpolated dts when we receive a new pts/dts */
487 if( p_sys->i_last_ref_pts > 0 && !p_sys->b_second_field )
488 p_sys->i_interpolated_dts = p_sys->i_last_ref_pts;
489 if( p_sys->i_dts > 0 ) p_sys->i_interpolated_dts = p_sys->i_dts;
491 if( !p_sys->b_second_field )
492 p_sys->i_last_ref_pts = p_sys->i_pts;
495 p_pic->i_dts = p_sys->i_interpolated_dts;
496 p_sys->i_interpolated_dts += i_duration;
498 /* Set PTS only if we have a B frame or if it comes from the stream */
499 if( p_sys->i_pts > 0 )
501 p_pic->i_pts = p_sys->i_pts;
503 else if( p_sys->i_picture_type == 0x03 )
505 p_pic->i_pts = p_pic->i_dts;
512 switch ( p_sys->i_picture_type )
515 p_pic->i_flags |= BLOCK_FLAG_TYPE_I;
518 p_pic->i_flags |= BLOCK_FLAG_TYPE_P;
521 p_pic->i_flags |= BLOCK_FLAG_TYPE_B;
525 p_pic->i_length = p_sys->i_interpolated_dts - p_pic->i_dts;
528 msg_Dbg( p_dec, "pic: type=%d dts="I64Fd" pts-dts="I64Fd,
529 p_sys->i_picture_type, p_pic->i_dts, p_pic->i_pts - p_pic->i_dts);
533 p_sys->p_frame = NULL;
534 p_sys->pp_last = &p_sys->p_frame;
535 p_sys->b_frame_slice = VLC_FALSE;
537 if( p_sys->i_picture_structure != 0x03 )
539 p_sys->b_second_field = !p_sys->b_second_field;
543 p_sys->b_second_field = 0;
547 p_sys->b_cc_reset = VLC_TRUE;
548 p_sys->i_cc_pts = p_pic->i_pts;
549 p_sys->i_cc_dts = p_pic->i_dts;
550 p_sys->i_cc_flags = p_pic->i_flags;
553 if( !p_pic && p_sys->b_cc_reset )
555 p_sys->b_cc_reset = VLC_FALSE;
556 cc_Flush( &p_sys->cc );
560 * Check info of current fragment
562 if( p_frag->p_buffer[3] == 0xb8 )
564 /* Group start code */
566 p_sys->i_seq_old > p_sys->i_frame_rate/p_sys->i_frame_rate_base )
568 /* Usefull for mpeg1: repeat sequence header every second */
569 block_ChainLastAppend( &p_sys->pp_last, block_Duplicate( p_sys->p_seq ) );
572 block_ChainLastAppend( &p_sys->pp_last, block_Duplicate( p_sys->p_ext ) );
575 p_sys->i_seq_old = 0;
578 else if( p_frag->p_buffer[3] == 0xb3 && p_frag->i_buffer >= 8 )
580 /* Sequence header code */
581 static const int code_to_frame_rate[16][2] =
583 { 1, 1 }, /* invalid */
584 { 24000, 1001 }, { 24, 1 }, { 25, 1 }, { 30000, 1001 },
585 { 30, 1 }, { 50, 1 }, { 60000, 1001 }, { 60, 1 },
586 /* Unofficial 15fps from Xing*/
588 /* Unofficial economy rates from libmpeg3 */
589 { 5, 1001 }, { 10, 1001 }, { 12, 1001 }, { 15, 1001 },
590 { 1, 1 }, { 1, 1 } /* invalid */
593 if( p_sys->p_seq ) block_Release( p_sys->p_seq );
594 if( p_sys->p_ext ) block_Release( p_sys->p_ext );
596 p_sys->p_seq = block_Duplicate( p_frag );
597 p_sys->i_seq_old = 0;
600 p_dec->fmt_out.video.i_width =
601 ( p_frag->p_buffer[4] << 4)|(p_frag->p_buffer[5] >> 4 );
602 p_dec->fmt_out.video.i_height =
603 ( (p_frag->p_buffer[5]&0x0f) << 8 )|p_frag->p_buffer[6];
604 p_sys->i_aspect_ratio_info = p_frag->p_buffer[7] >> 4;
606 /* TODO: MPEG1 aspect ratio */
608 p_sys->i_frame_rate = code_to_frame_rate[p_frag->p_buffer[7]&0x0f][0];
609 p_sys->i_frame_rate_base =
610 code_to_frame_rate[p_frag->p_buffer[7]&0x0f][1];
612 p_dec->fmt_out.video.i_frame_rate = p_sys->i_frame_rate;
613 p_dec->fmt_out.video.i_frame_rate_base = p_sys->i_frame_rate_base;
615 p_sys->b_seq_progressive = VLC_TRUE;
616 p_sys->b_low_delay = VLC_TRUE;
618 if ( !p_sys->b_inited )
620 msg_Dbg( p_dec, "size %dx%d fps=%.3f",
621 p_dec->fmt_out.video.i_width, p_dec->fmt_out.video.i_height,
622 p_sys->i_frame_rate / (float)p_sys->i_frame_rate_base );
626 else if( p_frag->p_buffer[3] == 0xb5 )
628 int i_type = p_frag->p_buffer[4] >> 4;
630 /* Extension start code */
634 static const int mpeg2_aspect[16][2] =
636 {0,1}, {1,1}, {4,3}, {16,9}, {221,100},
637 {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1},
642 /* sequence extension */
643 if( p_sys->p_ext) block_Release( p_sys->p_ext );
644 p_sys->p_ext = block_Duplicate( p_frag );
646 if( p_frag->i_buffer >= 10 )
648 p_sys->b_seq_progressive =
649 p_frag->p_buffer[5]&0x08 ? VLC_TRUE : VLC_FALSE;
651 p_frag->p_buffer[9]&0x80 ? VLC_TRUE : VLC_FALSE;
654 /* Do not set aspect ratio : in case we're transcoding,
655 * transcode will take our fmt_out as a fmt_in to libmpeg2.
656 * libmpeg2.c will then believe that the user has requested
657 * a specific aspect ratio, which she hasn't. Thus in case
658 * of aspect ratio change, we're screwed. --Meuuh
661 p_dec->fmt_out.video.i_aspect =
662 mpeg2_aspect[p_sys->i_aspect_ratio_info][0] *
664 mpeg2_aspect[p_sys->i_aspect_ratio_info][1];
668 else if( i_type == 0x08 )
670 /* picture extension */
671 p_sys->i_picture_structure = p_frag->p_buffer[6]&0x03;
672 p_sys->i_top_field_first = p_frag->p_buffer[7] >> 7;
673 p_sys->i_repeat_first_field= (p_frag->p_buffer[7]>>1)&0x01;
674 p_sys->i_progressive_frame = p_frag->p_buffer[8] >> 7;
677 else if( p_frag->p_buffer[3] == 0xb2 && p_frag->i_buffer > 4 )
679 cc_Extract( &p_sys->cc, &p_frag->p_buffer[4], p_frag->i_buffer - 4 );
681 else if( p_frag->p_buffer[3] == 0x00 )
683 /* Picture start code */
686 if( p_frag->i_buffer >= 6 )
688 p_sys->i_temporal_ref =
689 ( p_frag->p_buffer[4] << 2 )|(p_frag->p_buffer[5] >> 6);
690 p_sys->i_picture_type = ( p_frag->p_buffer[5] >> 3 ) & 0x03;
693 p_sys->i_dts = p_frag->i_dts;
694 p_sys->i_pts = p_frag->i_pts;
696 else if( p_frag->p_buffer[3] >= 0x01 && p_frag->p_buffer[3] <= 0xaf )
698 /* Slice start code */
699 p_sys->b_frame_slice = VLC_TRUE;
702 /* Append the block */
703 block_ChainLastAppend( &p_sys->pp_last, p_frag );